“Keepers” is set on an uninhabited island 20 miles from the Scottish coast as three lighthouse keepers arrive for their six-week shift. They stumble upon something that isn’t theirs to keep, triggering a tense battle for survival as personal greed replaces loyalty amid isolation and paranoia.

Producers are Andy Evans, Ade Shannon, and Sean Marley for Mad as Birds; Butler and Alan Siegel for G-Base; and Brian Oliver for Cross Creek Pictures. The project was brought to Cross Creek by Jason Seagraves, who is executive producing.

It was also recently annouced that Butler will star again as Secret Service agent Mike Banning in “Angel Has Fallen,” the third film in the “Fallen” franchise comprised of “Olympus Has Fallen” and “London Has Fallen.” That project is also selling at AFM.

CAA, which represents Butler, Alwyn, and Nyholm, will co-represent North American rights. Butler is also represented by Alan Siegel Entertainment; Alywn by Independent Talent Group; and Nyholm by United Agents. Mullan is repped by Markham, Froggatt and Irwin.